A new strain of actinobacteria, designated ABH26, was isolated from a Saharan soil in the Adrar region (Algeria), by the dilution agar plating method using a chitin-vitamins B medium supplemented with polymyxin and penicillin. The morphological studies showed that this strain represents a member of the Saccharothrix genus. Phylogenetic analysis showed that this strain had 16S rRNA gene sequence similarities ranging from 97.63% (with Saccharothrix violaceirubra NBRC 102064T) to 99.86% (with Saccharothrix xinjiangensis NBRC 101911T). Furthermore, strain ABH26 presented a strong activity against mycotoxigenic and phytopathogenic fungi including Aspergillus carbonarius (M333), A. flavus (NRRL 3251), A. westerdijkiae (ATCC 3174), Fusarium oxysporum f. sp. lini (Fol) and F. solani (Fsol). Additionally, the strain exhibited an important antimicrobial activity against many strains of the pathogenic yeast Candida albicans (M2, M3 and IPA200) and against methicillin resistant Staphylococcus aureus (MRSA 639c). Thus, four solvents (n-hexane, dichloromethane, ethyl acetate and n-butanol) were used for the extraction of produced antibiotic compounds. The highest antimicrobial activities were obtained using the butanolic extract. The thin layer chromatography (TLC) method showed two bioactive spots, named HAD1 and HAD2, which were reveled negatively by using chemical revelators (ninhydrin, naphtoresorcinol-sulfuric acid, ferrous iron chloride and formaldehyde-sulfuric). These results indicated the absence of amine group, sugar, hydroxamic acid, phenol and aromatic compound.
Actinobacteria, Saccharothrix, 16S rRNA, antimicrobial activity, TLC, chemical revelators